Functional surfaces that mimic surfaces found in nature include dry adhesive surfaces (i.e., gecko-mimetic surfaces), superhydrophilic surfaces (i.e., anti-fog surfaces), superhydrophobic water repellant surfaces (i.e., lotus leaf-mimetic surfaces), heat and light responsive surfaces, drag reducing surfaces (i.e., shark skin-mimetic surfaces), etc. In general, such surfaces have apparent utility and/or well established commercial potential. The particular functionality exhibited by any one of the various surfaces previously mentioned is often influenced by the specific type of and/or pattern formed by nano- and/or micro-structures arranged and/or supported on the respective surface. The function may also depend on the dimensions of these structures and/or patterns and/or the material characteristics of the structures.
For example, with regard to surface patterns and/or structures:                1) the foot of a gecko generally has a large plurality of hairs extending from and oriented at specific angles (e.g., perpendicular) with respect to an underlying and/or supporting surface, said hairs typically have diameters and lengths of about 5 and 100 microns, respectively—each hair is also generally split or divided at the distal end (i.e., the end away from or opposite the surface contacting end) into hundreds of finer hairs with diameters and lengths of about 0.1 and 10 microns, respectively;        2) the surface of a lotus leaf typically contains protrusions having diameters of about 10 microns, with additional structures having diameters of about 1 micron located on these protrusions; and        3) the surface of shark skin generally contains scales with dimensions of about 50-100 microns that protrude from the surface.        
In any event, desirable functions in numerous instances are generally a consequence of the micro- and/or nano-sized features and/or structures arranged and/or supported on the underlying surface. The particular function exhibited is generally influenced by one or more of the following factors: the dimensions of the micro-/nano-sized features or structures, the type and/or form of feature or structures, the material characteristics of the features or structures, the arrangement or pattern of the features or structures on the underlying and/or supporting surface, and the orientation of the features or structures with respect to the underlying and/or supporting surface, i.e., the specific angle(s) at which the features or structures are arranged and/or supported on the underlying surface (e.g., roughly perpendicular).
Adhesive systems of fauna (e.g., such as that of the foot of geckos) can consist of structured protruding fibers with dimensions ranging from a few hundred nanometers to a few microns, and some such fiber based “adhesive” systems are capable of dry operation, e.g., as in the case of geckos and certain spiders. Gecko adhesion is one example of a naturally occurring fiber based dry adhesion. Gecko feet adhere to substrates with a diverse range of chemical compositions and topologies. The adhesion characteristics are maintained under water and in vacuum. The feet are self-cleaning, non-self-adhesive and form reversible bonds with surfaces to which they are adhered. The “adhesive” elements on Gecko feet are comprised of micro-scale fibers called setae that further branch at the ends into hundreds of nano-scale fibrils. Such hierarchical architectures ensure compliance and conformability of the adhesive system over a large array of length scales thereby facilitating intimate contact between the terminal contacting elements and contacted surfaces. Studies indicate that complete contact of all adhesive elements present on Gecko feet with a substrate would yield a bond capable of withstanding 1300 N of shear (parallel to substrate) force and 260 N of adhesive (perpendicular to substrate) force.
Nevertheless, high quality synthetic fiber based dry adhesive systems exhibiting multilevel hierarchical organizations are relatively difficult to fabricate. That is to say, while hierarchical organized architectures, i.e., exhibiting branching and/or progressive reduction in scale (e.g., from micrometer to nanometer size features) are characteristic of natural fiber based dry adhesive systems, heretofore, sufficiently high quality synthetic based systems mimicking the natural fiber based dry adhesive systems and/or suitably efficient and/or easy methods for manufacturing the same have not been developed.
Accordingly, a new and/or improved functional construction with micro- and/or nano-sized surface features or structures and/or a manufacturing method for the same is disclosed which addresses the above-referenced problems and/or others.